Because someone with the problem wrote it as a question, for an audience with the same problem, and had to make it legible to strangers. That constraint separates a thread title from a question asked on a call: a forum poster edits the sentence so an unknown reader will follow it, which is exactly the self-contained, fully specified form a prompt needs.
It also arrives in the shape that most reliably produces an AI answer. An audit of 55,393 trending queries collected 13 March to 21 April 2026 measured Google AI Overview activation at 64.7% for question-form queries against 9.5% for the rest, a difference of 6.8 times.1 Thread titles are overwhelmingly question-phrased, so the source needs almost no normalisation: strip the slang a stranger would not follow, drop the “anyone else?”, and the sentence is ready.
What it does not carry is attribution. You know a human wrote it and roughly when; you do not know whether they were your buyer, a competitor, or someone long out of the market. That is why this source sits below your own calls and search console.